Validity and reliability of OIDP and OHIP-14: a survey of Chinese high school students

BACKGROUND To determine the impact of oral diseases on everyday life, measures of oral quality of life are needed. In complementing traditional disease-based measures, they assess the need for oral care to evaluate oral health care programs and management of treatment. To assess the reliability and validity of the Oral Impact of Daily Performance (OIDP) and the short-form Oral Health Impact Profile (OHIP-14) among high school students in Xi'an, the capital of Shanxi province, China. METHODS Cross-sectional one-stage stratified random cluster sample using high schools as the primary sampling unit. Students completed self-administered questionnaires at school. The survey included the OHIP-14 and OIDP inventories, translated and culturally adapted for China, and global oral health and socio-behavioral measures. RESULTS A total of 5,608 students participated in the study, with a 93% response rate (mean age 17.2, SD 0.8, 52% females, 45.3% urban residents).The proportion experiencing at least one impact (at any frequency) during the previous six months was 62.9% for the OHIP-14 and 45.8% for the OIDP. Cronbach's alpha measured internal consistency at 0.85 for OHIP-14 and 0.75 for OIDP while Cohen's kappa varied between 0.27 and 0.58 for OHIP-14 items and between 0.23 and 0.65 for OIDP items. Kappa scores for the OHIP-14 and OIDP additive scores were 0.52 and 0.66, respectively. Both measures varied systematically and in the expected direction, with global oral health measures showing criterion validity. The correlation between OIDP and OHIP-14 was rs +0.65. That both measures varied systematically with socio-behavioral factors indicates construct validity. CONCLUSION Both the OIDP and OHIP-14 inventories had reasonable reliability and construct validity in relation to subjective global oral health indicators among adolescents attending high schools in China and thus appear to be useful oral health -related quality of life measures in this context. Overall, the OHIP-14 and OIDP performed equally well, although OHIP-14 had superior content validity due to its sensitivity towards less severe impacts.